Print This Page
Health Effects of Mercury
People are most often exposed to mercury by eating fish and shellfish that contain methyl mercury. "Fish Facts for Good Health" (Washington State Department of Health) provides information about mercury and fish.
Exposure also occurs by breathing mercury vapors (from spills or contaminated air), skin contact with mercury, practicing rituals that use mercury, and release of mercury from dental work. See Elemental Mercury.
The health impacts arising from exposure to mercury are documented by the Centers for Disease Control and Prevention and the National Academy of Sciences.
Infants and children
Children, including the unborn, are most vulnerable to mercury poisoning because their developing brains and nervous systems are sensitive to low-doses of methylmercury. Methylmercury exposure can affect thinking, memory, attention, language, fine motor skills and visual-spatial abilities (e.g., drawing).
Infants are exposed to methylmercury from their mothers, both in the womb and through breastfeeding. Children are exposed when they eat fish containing mercury.
Recent studies suggest that mercury concentrates in a mother’s umbilical cord blood. This means that fetal exposure to methylmercury is greater than the concentration of mercury measured in the mother’s blood. For that reason, pregnant women are cautioned to avoid fish containing mercury.
Adults
In adults, exposure to methylmercury affects the nervous system. Symptoms can include loss of peripheral vision, disturbing sensations (‘pins and needles’ feeling), problems with speaking, lack of coordination and muscle weakness. The National Academy of Sciences published a report by the National Research Council suggesting that methylmercury can impact the cardiovascular system, affecting blood pressure, heart rate and heart disease. Methylmercury may also interfere with the immune and reproductive systems of animals.
Native Americans
Exposure to methylmercury may be a problem for Native Americans, Asians, Pacific Islanders (Environmental Health Perspectives, 2006) and other groups groups that consume large amounts of fish. A Washington State Department of Health (2001) analysis of fish consumption rates found that some Native Americans are likely to exceed the Department of Health’s tolerable daily intake (TDI) for methylmercury.
For more information contact Taylor Watson, Health and Environmental Investigator, at taylor.watson@kingcounty.gov.
